Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id B6ACE2E3AD1 for ; Tue, 22 Jan 2008 04:57:02 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 82853-02-3 for ; Tue, 22 Jan 2008 04:56:55 -0400 (AST) Received: from mx01.bfk.de (mx01.bfk.de [193.227.124.2]) by postgresql.org (Postfix) with ESMTP id E32062E3AC7 for ; Tue, 22 Jan 2008 04:56:54 -0400 (AST) Received: from mx00.int.bfk.de ([10.119.110.2]) by mx01.bfk.de with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) id 1JHEw6-0006nU-Ct; Tue, 22 Jan 2008 09:56:50 +0100 Received: from fweimer by bfk.de with local id 1JHEw7-0000pg-3s; Tue, 22 Jan 2008 09:56:51 +0100 To: "Guillaume Smet" Cc: "Hannes Dorbath" , pgsql-performance@postgresql.org Subject: Re: 8.3 synchronous_commit References: <82d4rumfae.fsf@mid.bfk.de> <1d4e0c10801220049p7b184a52s1b2b2e86bc414395@mail.gmail.com> From: Florian Weimer Date: Tue, 22 Jan 2008 09:56:51 +0100 In-Reply-To: <1d4e0c10801220049p7b184a52s1b2b2e86bc414395@mail.gmail.com> (Guillaume Smet's message of "Tue, 22 Jan 2008 09:49:02 +0100") Message-ID: <821w8ame5o.fsf@mid.bfk.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200801/177 X-Sequence-Number: 28416 * Guillaume Smet: > On Jan 22, 2008 9:32 AM, Florian Weimer wrote: >> > Maybe it's just my test box.. single SATA-II drive, XFS on top of LVM. >> >> Ours was ext3, no LVM or RAID. > > Also with SATA? Yes, desktop-class SATA. > If your SATA disk is lying about effectively SYNCing the data, I'm > not that surprised you don't see any improvement. It still should be faster since the commit doesn't even have to leave the kernel write cache. For us, this is the common case because most non-desktop systems have battery-backed write cache anyway. > Being slower is a bit surprising though. Exactly. --=20 Florian Weimer BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstra=DFe 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99